Builtins

Code Stub Assembler: How V8 Writes Machine Code by Hand

Oct 23, 2026 16 min read Jay Hubbert

CSA is a typed API that builds a TurboFan graph rather than bytes, which is why the same builtin source compiles to x64, arm64 and ia32 unchanged.

V8 Internals Compiler Codegen Builtins

Torque: The DSL V8 Uses to Write Its Own Builtins

Oct 23, 2026 18 min read Jay Hubbert

Torque compiles .tq files into a typed IR and then into C++ that drives the Code Stub Assembler, producing a Code object plus a generated call descriptor.

V8 Internals Builtins Torque Compiler